<template>
  <div class="goods">
    <div class="list-wrapper" ref="listWrapper">
      <ul>
        <li v-for="(item, index) in goods" :key="index" class="menu-item " :class="{'current': currentIndex === index}" @click="selectMenu(index, $event)">
          <span class="text border-1px">
            <span v-show="item.type > 0" class="icon" :class="classMap[item.type]"></span>{{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <li v-for="(item, index) in goods" class="food-list-hook"">
          <h1 class="title">{{item.name}}</h1>
          <ul>
            <li v-for="foods in item.foods" class="foods-item border-1px">
              <div class="icon">
                <img :src="foods.image" width="57" height="57" @click="selectFood(foods, $event)">
              </div>
              <div class="content">
                <h2 class="name">{{foods.name}}</h2>
                <p class="desc">{{foods.description}}</p>
                <div class="extra">
                  <span class="count">月售{{foods.sellCount}}份</span><span>好评率{{foods.rating}}%</span>
                </div>
                <div class="price">
                  <span class="nowPrice">￥{{foods.price}}</span>
                  <span v-show="foods.oldPrice" class="oldPrice">￥{{foods.oldPrice}}</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <cartcontrol :food="foods"></cartcontrol>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>
    <shop-cart :select-foods="selectFoods" :delivery-price="seller.deliveryPrice" :min-price="seller.minPrice"></shop-cart>
    <food :food="selectedFood" ref="food"></food>
  </div>
</template>
<script>
  import axios from 'axios'
  import BScroll from 'better-scroll'

  import shopCart from '@/components/shopcart/shopCart'
  import cartcontrol from '@/components/cartcontrol/cartcontrol'
  import food from '@/components/food/Food'

  export default {
    props: {
      seller: {
        type: Object,
        default() {
          return {}
        }
      }
    },
    data() {
      return {
        goods: [],
        listHeight: [],
        scrollY: 0,
        selectedFood: {}
      }
    },
    components: {
      shopCart,
      cartcontrol,
      food,
    },
    created() {
      this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee']
    },
    mounted() {
      this.goodsInfo()
    },
    computed: {
      currentIndex() {
        for(let i in this.listHeight) {
          i = i * 1
          let height1 = this.listHeight[i]
          let height2 = this.listHeight[i + 1]
          if(!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
            return i
          }
        }
        return 0
      },
      selectFoods() {
        let foods = []
        this.goods.forEach((good) => {
          good.foods.forEach((food) => {
            if(food.count) {
              foods.push(food)
            }
          })
        })
        return foods
      }
    },
    methods: {
      goodsInfo() {
        axios.get('/api/data.json')
          .then(this.goods_json)
      },
      goods_json(res) {
        res = res.data.goods
        this.goods = res
        /*  页面刚渲染的时候，dom还没渲染出来就已经出事了initScroll，不起作用，使用异步 this.$nextTick()方法主要是用在随数据改变而改变的dom应用场景中  */
        this.$nextTick(() => {
          this.initScroll()
          this.calculateHeight()
        })
      },
      initScroll() {
        this.menuScroll = new BScroll(this.$refs.listWrapper, {
          click: true
        })

        this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
          click: true,
          probeType: 3
        })

        this.foodsScroll.on('scroll', (pos) => {
          this.scrollY = Math.abs(Math.round(pos.y))
          //console.log(this.scrollY)
        })
      },
      calculateHeight() {
        let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook')
        let height = 0
        this.listHeight.push(height)
        for(let item of foodList) {
          height += item.clientHeight
          this.listHeight.push(height)
        }
        //console.log(this.listHeight)
      },
      selectMenu(index, event) {
        /*  better-scroll会将点击事件去掉，如果滚动部分需要有点击事件，需要在参数里加上click：true。同时，在PC上或某些手机端，由于未成功将touchend事件move掉，点击事件会执行两次。better-scroll派发的event事件和原生js的event有属性上的区别，其中有一个属性为event._constructed。better-scroll派发的事件中event._constructed为true，原生点击事件中没有这个属性。  */
        if(!event._constructed) return//如果不存在这个属性,则为原生点击事件，不执行下面的函数
        let foodList = this.$refs.foodsWrapper.getElementsByClassName('food-list-hook')
        let el = foodList[index]
        this.foodsScroll.scrollToElement(el, 300)
      },
      selectFood(foods, event) {
        if(!event._constructed) return
        this.selectedFood = foods
        this.$refs.food.show()
        //console.log(this.selectedFood)
      }
    }
  }
</script>

<style scoped lang="stylus">
  @import '../../common/stylus/mixin.styl'

  .goods
    display: flex
    position: absolute
    top: 174px
    bottom: 46px
    width: 100%
    overflow: hidden
    .list-wrapper
      width: 80px
      flex: 0 0 80px
      background: #f3f5f7
      .menu-item
        display: table
        height: 54px
        line-height: 14px
        width: 56px
        padding: 0 12px
        &.current
          position: relative
          margin-top: -1px
          background: #fff
          font-weight: 700
          z-index: 1
          .text
            border-none()
        .text
          display: table-cell
          vertical-align: middle
          border-1px(rgba(7, 17, 27, 0.1))
          font-size: 12px
          .icon
            display: inline-block
            width: 12px
            height: 12px
            margin-right: 2px
            background-size: 100%
            background-repeat: no-repeat
            &.decrease
              bg-image('decrease_3')
            &.discount
              bg-image('discount_3')
            &.guarantee
              bg-image('guarantee_3')
            &.invoice
              bg-image('invoice_3')
            &.special
              bg-image('special_3')
    .foods-wrapper
      flex: 1
      .title
        padding-left: 14px
        height: 26px
        line-height: 26px
        border-left: 2px solid #d9dde1
        font-size: 12px
        color: rgb(147, 153, 159)
        background: #f3f5f7
      .foods-item
        display: flex
        margin: 18px
        padding-bottom: 18px
        border-1px(rgba(7, 17, 27, 0.1))
        &:last-child
          borer-none
          margin-bottom: 0
        .icon
          flex: 0 0 57px
          margin-right: 10px
        .content
          flex: 1
          .name
            margin: 2px 0 8px 0
            height: 14px
            line-height: 14px
            font-size: 14px
            color: rgb(7, 17, 27)
          .desc
            margin-bottom: 8px
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
          .extra
            line-height: 10px
            font-size: 10px
            color: rgb(147, 153, 159)
            .count
              margin-right: 12px
          .price
            font-weight: 700
            line-height: 24px
            .nowPrice
              margin-right: 8px
              font-size: 14px
              color: rgb(240, 20, 20)
            .oldPrice
              text-decoration: line-through
              color: rgb(147, 153, 159)
              font-size: 10px
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 12px

</style>